Considerations in the management of anaphylaxis

THE burden of food allergy and anaphylaxis has increased in Australia and other westernised countries over the past 20 years.

In Australia, for example, hospital admission rates for food-related anaphylaxis have increased ninefold from 2.0 to 18.2 per 100 000 population between the financial years of 1998–99 to 2018–19 (personal observation based on unpublished data), with a parallel increase in anaphylaxis fatalities. While the highest rates of food allergy and anaphylaxis have occurred in young children, we are observing a generational change, with accelerating rates in adolescents and young adults, in patients with food allergy that is unlikely to resolve (ie, those with peanut, tree nut, sesame seed or seafood allergy), and in whom the risk of fatal outcomes is highest.

The changing epidemiology of childhood food allergy and anaphylaxis poses a number of challenges: an impact on quality of life for patients and their carers, potential impact on growth and nutrition with unmonitored dietary restrictions, the personal and economic impact of a diagnosis, access to specialist services, and the need for education of patients, caregivers and health professionals, as previously discussed. Since 2010, a range of Australasian Society of Clinical Immunology and Allergy (ASCIA) online educational resources have been implemented, including e-training.

A number of environmental factors have been proposed to be driving increases in food allergy development (eg, filaggrin loss of function gene status, sensitisation to food via non-intact skin, early life microbiota, genetic and epigenetic influences, socio-economic status and location of residence, and vitamin D status/ultraviolet radiation exposure). In the past decade, however, high quality evidence has demonstrated the benefit of early introduction of allergenic food such as peanut (here and here), egg and dairy products in reducing the risk of childhood food allergy development.

These studies have led to changes in ASCIA Australian weaning guidelines for allergy prevention in 2008 to “no longer delay” introduction of allergenic foods, and in 2016, to “give early and often”. Changing guidelines have had a real-world impact, with rates of peanut introduction in Melbourne increasing from 28% in 2007–2011 to 88% in 2016–2018 in the first year of life. There is also some evidence that there has been some impact on food allergy, with challenge-proven peanut allergy dropping from 3.1% of those recruited 2007–2011 in a cohort study to 2.6% of those recruited in 2018–2019.

In the past 2 years, Australia has also had a Parliamentary Inquiry into Allergies and Anaphylaxis and the report from this Inquiry reflects the changing epidemiology and impact of food allergy and anaphylaxis in Australia. In 2015, a National Allergy Strategy was developed as a partnership between ASCIA and Allergy and Anaphylaxis Australia (A&AA), the peak allergy medical and patient support organisations in Australia. The aim of the Strategy is to provide educational resources to all levels of the community to reduce the risk of new food allergy development, to assist in the management of patients with pre-existent disease and hopefully, long term, to assist in development of a model of care for those with allergic disease.

The Nip Allergies in the Bub project undertaken by the National Allergy Strategy provides practical information to parents about how to introduce the common food allergens and keep them in the child’s diet to help reduce the risk of food allergy. In addition, SmartStartAllergy, a novel tool, was developed based on SmartVax created to monitor vaccine safety. SmartStartAllergy is a text message program, whereby general practices send text messages to parents of children encouraging them to introduce the common food allergens before one year of age and providing a link to the Nip Allergies in the Bub website. Parent-reported reactions are collected via an online survey and reactions indicative of allergy trigger an alert to the patient’s general practice.

For many, food allergy will remain a lifelong chronic personal health and financial burden for which there is currently no cure. This burden will only be addressed by development of an effective cure, while population disease incidence can only be reduced by identifying risk factors and development of effective prevention strategies, as well as curative therapies.

Until such goals are achieved, management of food-related anaphylaxis is underpinned by identification of potential triggers, patient and carer education on avoidance strategies and an ASCIA Action Plan for Anaphylaxis if accidental exposure occurs. As studies of fatal anaphylaxis have taught us, attention to the recumbent posture and early use of adrenaline has been shown to reduce the risk of fatal outcomes.

The Pharmaceutical Benefits Scheme subsidy of an adrenaline autoinjector device in 2003 for the acute management of anaphylaxis in Australia was a welcome initiative. There are, however, a few issues that are yet to be resolved regarding adrenaline administration:

• conflicting current manufacturer prescribing information that recommends a dose of 0.15 mg adrenaline for weight 15–30 kg and 0.30 mg for ³ 30 kg (there is no adrenaline autoinjector recommendation for < 15 kg);
• ASCIA recommendations for 0.15 mg adrenaline for weight 7.5–20 kg, 0.30 mg adrenaline for those weighing ³ 20 kg, and 0.50 mg for weight greater than 50 kg; and
• recommendations that the dose of adrenaline administered for the treatment of anaphylaxis be 0.01 mg/kg, which would suggest that the average adult of ³ 50 kg might be given a suboptimal dose of adrenaline with the adrenaline autoinjector currently available (EpiPen, Viatris).

In the past 14 years, Australia has been subject to intermittent adrenaline autoinjector shortages (here, here and here) from devices obtained from abroad and, at times, relatively short shelf-life, increasing the cost of care and demand for medical review and additional anxiety about whether expired devices are effective and can still be used beyond expiry.

The forthcoming return of the new version of the Anapen (Allergy Concepts P/L) adrenaline autoinjector device to the Australian market may relieve some of the above shortage and weight dose-related issues. These devices approved by the Therapeutic Goods Administration are described as having shelf lives of 21–24 months, with a higher dose of 0.50 mg available for individuals weighing > 50 kg.

Prescribing of different devices will be at the discretion of individual specialists, based, for example, on patient weight, age and other factors. There are, however, important caveats when prescribing EpiPen or Anapen:

• device administration is very different for the two devices available in Australia, so that device-specific training is essential (ASCIA and A&AA resources are available);
• an ASCIA Action Plan specific to the device prescribed must be supplied to the patient;
• prescribing the device must be brand-specific and disallowing pharmacy-based substitution must be made very clear on any prescription written (even more important given recent moves to generic prescribing in electronic prescription software making it relatively easy to inadvertently prescribe generic adrenaline, as at least one software package [Medical Director] allows brand substitution for adrenaline autoinjector);
• patients, their carers and dispensing pharmacists must ensure that the correct device has been dispensed and the patient/carer has been shown how to use the device (eg, online animation resources); and
• those charged with treating anaphylaxis and administering an adrenaline autoinjector device (eg, school and childcare staff) are trained appropriately, a policy mandated in some jurisdictions in Australia, but sadly missing or ad hoc in others, with additional disparities between government-run and private educational facilities.

We support the recommendations of the House of Representatives Standing Committee on Health, Aged Care and Sport, including a national standardised approach to allergy management, all staff at Australian primary and secondary schools to receive nationally consistent education and training for recognising and responding to anaphylaxis, and the development of minimum standards of allergy training for health professionals.

Until the recommendations are acted on by government, we encourage those involved in the care of patients with food allergy and anaphylaxis to update their skills in this area utilising current resources.

Dr Raymond Mullins is a consultant physician in immunology and allergy in private practice in Canberra. He is a Past President of ASCIA, and remains an active member of various ASCIA committees while continuing clinical research and patient care.

Maria Said, a registered nurse, is Chief Executive Officer of Allergy and Anaphylaxis Australia (A&AA). She is also the co-chair of the National Allergy Strategy, a partnership between ASCIA and A&AA, which was launched in Sydney in August 2015.

Sandra Vale is the National Allergy Strategy Manager and former ASCIA Education Officer. Sandra is undertaking research into implementing the ASCIA Guidelines for infant feeding and allergy prevention.

Associate Professor Richard Loh OAM is a paediatric clinical immunologist, specialising in the treatment of children with allergic diseases or recurrent infections at Perth Allergy. He was involved in the development and implementation of the National Allergy Strategy. 

None of the authors have received sponsorship or payment for writing this article and neither of the adrenaline autoinjector manufacturers have had input into its content.

The statements or opinions expressed in this article reflect the views of the authors and do not represent the official policy of the AMA, the MJA or InSight+ unless so stated.